High-temperature mechanical properties and thermal shock behavior of ternary-layered MAB phases Fe2AlB2

The high-temperature flexural and compressive strengths, and thermal shock behavior in water of Fe2AlB2 were investigated from room-temperature (RT) to 1000 degrees C. The flexural strength varies in a narrow range of 200-250 MPa from room temperature to 1000 degrees C, without evident plastic deformation. The compressive strength of Fe2AlB2 decreases gradually from 1992 +/- 176 MPa at RT to 1482 +/- 127 MPa at 600 degrees C. However, the further increasing temperature results in quicker decrease of the compressive strength to 245 +/- 7 MPa at 1000 degrees C although no plastic deformation is present in the temperature range of 600-800 degrees C. The brittle-ductile transition temperature (BDTT) is higher under flexure (> 1000 degrees C) than compression (800-900 degrees C), which is attributed to the higher shear stress under compression. The water-quenched flexural strength exhibits features consistent with the quasi-static propagation of "long initial cracks", with a critical temperature difference of 200-300 degrees C. The deduced cracks contribute to the decreasing retained strength. The uniaxial compress during hot pressing results in a weak anisotropy of mechanical properties.